On Thu, 10 May 2018 15:17:19 +0100, "Dave Plowman (News)"
wrote:

In article ,
T i m wrote:
One to be careful of is not having it on Amps when measuring Volts ...
or having it on a too low range when measuring Amps (although some are
fuse protected).

Indeed. On one of mine, a replacement fuse costs more than a cheap DVM.
I tend to use a clamp meter first to make sure there's nothing silly, then
the DVM for an accurate reading.

That's the thing isn't it, to be able to do much of this easily,
accurately and safely (to both the user and the equipment) you really
need quite a range of equipment (and not all of it that expensive).

Like two DMM's with one setup on volts and the other amps so you can
measure both simultaneously (and not necessarily at the same place).

One tool I've come across recently that has so far been very good at a
very basic go/no-go level of vehicle faultfinding is the voltage probe
thing:

http://www.sealey.co.uk/PLPageBuilde...oduc tid=7224

(found cheaper elsewhere etc).

Test for the presence of 6-24 volts or ground (red / green LED) and /
or apply the vehicle voltage or earth to a point.

A classic example of it's usage would be the kitcars o/s indicator
repeater not working.

Take the lamp out and apply the earth clip to the lamp body and push
the rocker switch forward to apply a live to the lamp contact and lamp
lights (so good lamp).

With the o/s indicator running, touch the probe on the centre contact
in the lamp holder and watch the LED go red / green in sync with the
other indicators (indicator feed to lamp holder ok).

Put the lamp back in, pull the toggle switch backwards and touch the
probe on the lamp case to give it an earth, lamp flashes.

Touch the probe (still 'earth') on the lamp holder beside the lamp,
lamp flashes.

Touch the probe (still 'earth') on the rest of the metal body of the
fitting, no lamp flash?

Release toggle and check status of the metal fitting and it shows
earth.

Fault, a high resistance or open circuit in the joint where the lamp
bayonet female is peened into the metal base of the fitting itself!

Temp solution, run some bare copper wire from beside lamp base to the
lens retaining pillar whilst I order a new pair of fittings. ;-)

Cheers, T i m